We present an array of [4+2] cycloaddition reactions between ketene enolates, catalytically derived from acid chlorides and cinchona alkaloid nucleophilic catalysts in the presence of stoichiometric base, and o-benzoquinone derivatives. These cycloaddition reactions proceed with
excellent stereochemical control (up to >99% ee). In fact, for both the o-benzoquinone imide and the o-benzoquinone diimide manifolds, these Diels-Alder reactions occurred with uniformly >99% ee. The wide scope of this methodology provides access to a diverse
range of biologically and synthetically useful chiral products, including ?-hydroxyesters, non-natural ?-amino acids, quinoxalinones, and many others, all with remarkable, catalytic control of regio- and stereochemistry.
我们提出了一系列[4+2]环加成反应,其中酮烯醇酸盐由酸氯化物和金鸡纳生物碱亲核催化剂催化生成,在等当量碱存在下,与邻苯二醌衍生物发生反应。这些环加成反应具有出色的立体化学控制(高达>99% ee)。事实上,对于邻苯二醌亚胺和邻苯二醌二亚胺两种反应体系,这些Diels-Alder反应均以均匀的>99% ee进行。这种方法的广泛适用范围提供了对各种生物学和合成上有用的手性产物的访问,包括α-羟基酯、非天然α-氨基酸、喹啉酮等,所有这些产物都具有显著的催化控制区域和立体化学。